The present invention relates generally to orthodontia and more particularly to an improved method and apparatus for orthodontic correction utilizing tapered arch wires and tapered wire receiving slots in the arch wire brackets.
As is well known to those versed in orthodontics, initial positioning and application of brackets and arch wires is a tedious and time consuming procedure and especially difficult when the patients are youngsters. While there have been a significant number of devices developed for positioning of brackets and arch wires, considerable problems remain. In addition, reducing the number of arch wires and the replacement of arch wire brackets, particularly in lingual braces, is highly desirable.
In the science of orthodontics there has been developed two techniques and the associated apparatus for straightening teeth. The "edgewise" technique was developed first and employs orthodontic brackets having a horizontal slot for receiving a single rectangular arch wire. The arch wire is retained by brackets attached to adjacent teeth and is bent to achieve "tipping" (rotation of the tooth about the buccal-lingual axis toward or from adjacent teeth) or "torquing" (rotation of the tooth about the mesial-distal axis toward or from the palate). The rectangular arch wire is usually relatively large in diameter and is painful to the patient since large rotational forces are generated.
The "light-wire" technique was developed in an attempt to avoid the painfully large rotational forces of the "edgewise" technique. A thin round wire is utilized to reduce the rotational forces while achieving results which are as effective as those obtained with large rectangular or round wires. In addition there is less friction between the bracket and the wire so that the teeth can move much more easily.
U.S. Pat. No. 3,327,393 Brader discloses an orthodontic arch wire edgewise bracket having a pair of coacting resilient arms which hold a conventional arch wire in the bracket. The resilient arms are spaced and rounded so as to provide an opening aligned with the entrance of the wire receiving chamber. The arch wire may be either rectangular or trapezoidal with the trapezoidal configuration augmenting the differences and the resistance of the lip surfaces to the insertion and removal of the arch wires, thereby making it easier to insert the arch wire and more difficult to remove it. The wire receiving socket is described in Brader as being shaped to cooperate with the arch wire; however, there is no teaching as to how they cooperate.
U.S. Pat. No. 3,964,165 Stahl, discloses a wire retaining bracket made of an elastomeric polymer. The bracket has a horizontal slot with a liner formed of a substantially rigid material such as metal. The bracket may be molded around the liner to form an integral unit. However, removal or replacement of the liner is not suggested.
At the present time, the most popular orthodontic technique is called the Begg technique after its inventor. It employs a rectangular bracket having a rectangular slot and a round wire. The round wire is used to exert force against the tooth by means of the bracket. The crown of the tooth goes backward and the tip of the root comes forward. Because the wire is round and the bracket is narrow, there is little friction and movement is rapid, but since only the root is moving forward, the net effect is not desirable.
One way of solving the problem of uncontrolled tipping is the use of rectangular wire. When a tooth is retracted on rectangular wire it moves back more or less in a bodily fashion with little or no tipping. However, movement of the tooth in a force vector other than directly horizontal or vertical is not easily accomplished with rectangular wire.
Accordingly, it is an object of the present invention to provide an improved apparatus for the orthodontic correction of teeth which utilizes a tapered arch wire and a tapered wire receiving slot so as to effect orthodontic correction in three planes of space simultaneously.
It is an additional object in one embodiment of the present invention to provide an apparatus for orthodontic correction which utilizes a plurality of bracket inserts for selectively increasing or reducing friction when changing the position of the arch wire and for altering the force vector applied to the tooth being corrected.
It is an additional object of the present invention to provide a system for orthodontic correction in which the arch wire, the brackets and the inserts are visually coded so that perfect duplicability of orthodontic correction may be effected.
Finally, it is an additional object of the present invention to provide a nathological method of orthodontia in which the entire patient is treated.